Spatial Filter Modulation for Object Length Measurement
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Solution Overview
Problem
Existing techniques for determining object characteristics, such as length, using light emanating from objects in a flow path are limited in accuracy and throughput, particularly in high-speed cytometry applications, as they rely on simple intensity modulation and pulse width measurement without advanced spatial filtering.
Innovation Solution
A system employing a spatial filter with alternating mask features of different light transmission characteristics modulates light intensity as objects pass through, generating time-varying electrical signals from which pulse widths are measured to determine object length, enabling precise characterization of objects in flow cytometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simple intensity modulation without spatial filtering is used, then device complexity is reduced, but measurement precision of object length deteriorates
Solution Approach 1:
The spatial filter divides the light transmission path into multiple discrete regions with different transmission characteristics (first and second features with different light transmission characteristics). This segmentation allows the system to encode spatial information about object length into distinct intensity modulation patterns, thereby improving measurement precision without requiring overly complex filtering arrangements.
Solution Approach 2:
Different regions of the spatial filter are assigned different light transmission characteristics (some regions transmit light, others block or partially transmit light). This local differentiation creates unique intensity modulation signatures for objects of different lengths, enabling precise length determination while maintaining relatively simple filter construction.
2Measurement precision
If advanced spatial filtering with alternating mask features is employed, then measurement precision of object length is improved, but device complexity increases
Solution Approach 1:
The spatial filter employs alternating mask features arranged in a periodic pattern along the flow direction. This periodic structure creates regular intensity modulation patterns that are easier to analyze and process, improving measurement precision while avoiding the need for irregular or highly complex filter geometries.
Solution Approach 2:
The mask features in the spatial filter have varying light transmission characteristics (different transmission parameters) that can be adjusted or selected based on the measurement requirements. By changing these parameters systematically, the system achieves high measurement precision without requiring complex mechanical or optical configurations.
3Productivity
If pulse width measurement is performed without spatial modulation, then throughput is maintained, but measurement precision deteriorates
Solution Approach 1:
The system replaces complex mechanical measurement systems with an optical-based spatial modulation approach. By using a spatial filter to modulate light intensity according to object characteristics, the system achieves high measurement precision while maintaining high throughput through non-contact, optical-only measurement that can process objects rapidly in flow.
4Measurement precision
If spatial modulation with alternating transmission features is used, then object length measurement accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
The spatial filter with alternating mask features automatically encodes object length information into the intensity modulation pattern without requiring manual intervention or complex operation. The system self-calibrates and self-measures by comparing the modulation pattern against reference characteristics, improving measurement precision while maintaining ease of operation through automated processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy and throughput of object length determination by analyzing pulse widths at specific amplitude extremums, effectively handling varying object sizes and velocities, even in high-throughput cytometry settings.
Implementation Method 1
The spatial filter has a plurality of mask features comprising first features alternating with second features along the flow direction, the first features having first light-transmission characteristics and the second features having second light transmission characteristics, different from the first light transmission characteristics
Implementation Method 2
A detector is positioned to sense light emanating from at least one object moving in a flow path... generates a time varying electrical signal comprising a sequence of time modulated pulses responsive to the sensed light
Data Source
AI summary
Spatially modulated light emanating from an object moving along a flow path is used to determine various object characteristics including object length along the flow direction. Light emanating from at least one object moving along in a flow path along a flow direction of a spatial filter is sensed. The intensity of the sensed light is time modulated according to features of the spatial filter. A time varying electrical signal is generated which includes a plurality of pulses in response to the sensed light. Pulse widths of at least some of the pulses are measured at a fraction of a local extremum of the pulses. The length of the object along the flow direction is determined based on the measured pulse widths.